function before(node) {
    if (node) {
        console.log(node);
        before(node.left);
        before(node.right)
    }
}

function middle(node) {
    if (node) {
        middle(node.left);
        console.log(node);
        middle(node.right)
    }
}

function after(node) {
    if (node) {
        after(node.left);
        after(node.right)
        console.log(node);
    }
}